1. Field of the Invention
The present invention relates to a clip formed of resin which is utilized for fixing, for example, components to be incorporated inside an automobile or an electric appliance, to a panel part of a vehicle body or a body of the electric appliance, or for fixing another panel to this panel part.
2. Description of the Related Art
Generally, the clip of this type has a head part adapted to be contacted with a peripheral edge of a fitting hole in a panel to be fitted, and a leg part which is extended from the head part and adapted to be inserted into the fitting hole thereby to be engaged with the peripheral edge of the fitting hole at a back side thereof.
As an example of such clip, Japanese Utility Model Registration No. 2571374 as described below discloses a clip formed of resin and including a head part adapted to be attached to an object for mounting (for example a door trim of an automobile), a leg part adapted to be inserted into a fitting hole in a vehicle body, wherein the leg part has a post suspended from a center part of a lower face of the head part, and at least three skeleton pieces radially protruded from the post along a vertical direction of the post, having such a protruding width that the skeleton pieces can be inserted into the fitting hole with substantially no clearance, and elastic engaging pieces allowable to be inwardly flexed are extended from distal ends of the skeleton pieces in a circumferential direction of a circle which is drawn around the post making the skeleton pieces as a radius, engaging edges which can be engaged with the edge of the fitting hole being formed on an outer peripheral face of the elastic engaging pieces at positions adjacent to their free ends, the elastic engaging pieces being further provided with connecting portions to the skeleton pieces in the vertical direction of the skeleton pieces, lower edges of the circumferentially extended portions of the elastic engaging pieces being formed as free ends along their entire length.
On the other hand, Japanese Patent No. 3450342 discloses a clipping device formed of synthetic resin and including a head part, and a locking leg which is suspended from a lower face of the head part and adapted to be inserted into a through hole in a panel thereby to be fixed to the panel, wherein the locking leg is straightly suspended from a center part of the lower face of the head part, and provided with four projections which are radially projected outwardly from its center in a longitudinal direction of the locking leg, the clip further includes a shaft core part making a substantial outer diameter of a circle connecting respective distal ends of the four projections smaller than a diameter of the through hole in the panel, and four elastic locking pieces arranged between the four projections of the shaft core part at determined intervals from the respective projections, with their upper ends joined to a base part of the shaft core part or the lower face of the head part, and with their lower ends joined to a leg end of the shaft core part to be integral with the shaft core part, characterized in that the four elastic locking pieces are respectively formed with swelled parts on their outside faces in the middle of their length, a substantial diameter of a circle connecting the swelled parts is made larger than the diameter of the through hole in the panel, whereby on occasion of reducing the diameter while the elastic locking pieces pass the through hole, the elastic locking pieces are retracted into the spaces between the projections and flexed toward the center part to be reduced in diameter, whereas on occasion of locking, the elastic locking pieces are protruded from the spaces between the projections by elastic restoring force, thereby to hook and lock the swelled parts on an edge of the through hole in the panel.
In case where a door trim of an automobile, for example, is fixed to a body panel, a clip is fitted to the door trim in advance, by engaging a head part of the clip with the door trim, and thereafter, a leg part of the clip is inserted and fixed into a fitting hole in the body panel while grasping the door trim by hand. However, the leg part of the clip is likely to be displaced from the fitting hole due to assembling variations when the vehicle has been assembled, and a position of the fitting hole cannot be easily confirmed by a worker, after the body panel has been covered with the door trim. For this reason, it has sometimes happened that the leg part cannot be straightly inserted into the fitting hole, but may be inclined with respect to the fitting hole when inserted. Moreover, there has been such a trouble that a prying force (a pulling force in a diagonal direction) may be exerted on the clip, even after the door trim and the body panel have been assembled together, due to variations or distortions in molding them.
When the leg part has been diagonally inserted, or the prying force has been applied to the clip in this manner, it has sometimes happened that a particular one of the elastic engaging pieces is excessively flexed, and exceeds a limit of elasticity of the elastic engaging piece, resulting in collapse or break of the particular elastic engaging piece. Consequently, it has sometimes happened that a sufficient locking force with respect to the fitting hole cannot be obtained, and the clip may cause a backlash or may be disengaged.
As a countermeasure, in the clip in the above described Japanese Utility Model Registration No. 2571374, an amount of flexure of the engaging pieces can be restricted to some extent when they have been diagonally inserted, because the at least three skeleton pieces are protruded from the post in a radial direction. However, in this clip, the ends of the engaging pieces extended from the distal ends of the skeleton pieces in a circumferential direction of the circle which is drawn around the post making the skeleton pieces as the radius are formed as the free ends which are not coupled to the skeleton pieces or the head part. Accordingly, there has been such probability that in case where a local pressure has been applied to the engaging pieces when they have been diagonally inserted, a particular engaging piece may be excessively flexed to cause plastic deformation, and engaging ability may be deteriorated.
On the other hand, in the clip in the above described Japanese Patent No. 3450342, an amount of flexure of the elastic locking pieces can be restricted to some extent when they have been diagonally inserted, because the shaft core part is provided with the four projections which are projected radially. However, because the clip includes the four projections which are projected radially, and the four elastic locking pieces which are arranged with gaps with respect to these projections, the connecting portions between the distal ends of the elastic locking pieces and the shaft core part are made rather thinner. Accordingly, there has been such a problem that the connecting portions may be likely to be broken.